Various types of drip irrigation emitters are known in the art and in the patent literature. U.S. Pat. No. 3,981,452 to Eckstein describes a continuous extruded drip irrigation line employing drip irrigation elements having a generally circular cross section. Drip irrigation lines according to this patent have enjoyed considerable commercial success throughout the world.
Beginning in 1979, drip irrigation conduits were introduced to the market which employed drip irrigation elements having a non-circular circular cross section heat welded to the interior surface of an extruded conduit.
U.S. Pat. No. 4,728,042 to Gorney and Dinur, describes a continuous extruded drip irrigation line wherein the drip irrigation elements have a non-circular cross section and are mounted onto the interior wall of an extruded drip irrigation conduit along less than its entire circumference. A flow rate reduction path is defined between the interior wall and part of each element.